MOnitor to MpC HELP

could someone help me out? So i bought monitors for my MP hooked them up to the stereo out of my MPC i even got the adapter that could connect to both left and right but i only still hear one side out of my monitors

what mpc do you have? Im working with the MPC 2000 OG. On the back the MPC has 2 outputs ( L and R channel (as i thought all did)). I dont understand why you would have to an adapter?

More info please.

Can we assume you bought powered monitors ? If not you still need to buy an amp.

You say 'adapter so I can hook up both left and right outputs of the MPC"
Why an adapter? Is it a set of computer monitors that have one stereo miniplug, that bridges to both? If not, shouldn't it be one 1/4 inch cable to each speaker independantly, left and right? Clarify, thanks.